Heart disease is the no1 killer in the UK and throughout the developed world, responsible for 1 in 3 deaths.
Statins are often seen as a powerful tool in the fight against heart disease (aka cardiovascular disease or CVD). Statins are prescribed to many millions of people worldwide for lowering cholesterol and preventing heart attacks and strokes. Yet, as with any medication, the question arises: do the benefits always outweigh the risks?
At ProLongevity, we’re passionate about delivering evidence-based information that helps people make informed decisions about their own health. One of the most valuable tools in understanding the effectiveness of medical interventions and treatments like statins is the concept of Number Needed to Treat (NNT) and Number Needed to Harm (NNH). So in this blog, we’ll explain these concepts and what they mean for the prevention of heart disease. We’ll also explain what we mean by “primary” and “secondary” prevention, referencing an independent medical resource TheNNT.com, which uses real-world data to assess the effectiveness of various treatments.
Understanding NNT and NNH
What Is NNT?
The Number Needed to Treat (NNT) is a simple but powerful measure used to determine how many patients need to receive a particular treatment for one person to benefit. For example, if the NNT for a medication is 50, that means 50 people must take the drug for one person to avoid a negative health outcome (such as a heart attack). The other 49 people receive no benefit.
What Is NNH?
Conversely, the Number Needed to Harm (NNH) indicates how many people need to be treated before one person experiences a harmful side effect from the drug. A low NNH suggests that side effects are more common, while a high NNH implies that side effects are rarer.
Together, NNT and NNH provide a clearer picture of the risk-benefit ratio of a treatment.
What is Primary Prevention?
Primary prevention is an examination of the the ways to prevent the onset of a disease in people who have not yet developed any symptoms or experienced any related health events. In the context of cardiovascular disease, primary prevention involves stopping the first heart attack, stroke, or other heart-related conditions.
Put simply its about treating “at-risk” individuals before they even get the disease. For example, if a person has high cholesterol, high blood pressure, or diabetes but has never had a heart attack or stroke, they may be prescribed statins or other medications to reduce their risk of experiencing such an event in the future.
Key Points for Primary Prevention:
- The person has not had a heart attack or stroke.
- Treatment is aimed at lowering risk factors (like bad cholesterol or high blood pressure) to prevent the first event.
- The goal is to prevent the development of cardiovascular disease in an at-risk individual.
What is Secondary Prevention?
Secondary prevention is aimed at preventing the recurrence of a disease or health event in people who have already been diagnosed with it. In cardiovascular terms, secondary prevention refers to interventions intend to prevent further heart attacks or strokes in people who have already experienced at least one.
So if someone has already had a heart attack, secondary prevention efforts would involve using statins (or other treatments) to reduce the risk of having another heart attack or other related complications.
Key Points for Secondary Prevention:
- The person has already had a heart attack, stroke, or another cardiovascular event.
- Treatment focuses on preventing future events.
- The goal is to reduce the risk of further damage in someone who already has cardiovascular disease.
Why Does it Matter?
The distinction between primary and secondary prevention is crucial because the benefits of treatments like statins are different for each group. In secondary prevention, where the risk of another heart attack or stroke is much higher, statins have a clear benefit and a lower Number Needed to Treat (NNT), meaning fewer people need to be treated to see a benefit. In primary prevention, where the person hasn’t yet had a cardiovascular event, the benefit is tiny, with a much higher NNT. This raises questions about whether the risks (side effects) are worth it in this generally low-risk group.
In summary:
- Primary prevention = preventing the first occurrence of disease.
- Secondary prevention = preventing further events in people who already have the disease.
The Benefits of Statins
- Cardiovascular Event Reduction: Primary and Secondary Prevention
Statins have shown some benefits in reducing cardiovascular events, particularly in secondary prevention. In primary prevention the benefit is much less clear-cut.
- Secondary Prevention: In patients who have already suffered a heart attack or stroke, statins reduce the risk of further cardiovascular events. According to data from TheNNT.com, the NNT for statins in secondary prevention is 83. This means that 83 people need to take statins for 5 years for one person to avoid a non-fatal cardiovascular event. Of course the remaining 82 people don’t derive ANY benefit
- Primary Prevention: For people who have not yet had a heart attack or stroke, the NNT for statins is 104. This means 104 people must be treated for 5 years for one to avoid a cardiovascular event. (The remaining 103 people don’t get ANY benefit) The effectiveness is lower in this group because the baseline risk is lower compared to those who have already had a heart attack or stroke.
The Harms and Controversies of Statins
While the benefits in secondary prevention are well-established, statins are not without their risks. Some people experience side effects that may significantly affect their quality of life. Understanding the NNH for statins helps to weigh these risks.
Muscle Pain and Weakness (Myopathy)
One of the most frequently reported side effects of statins is muscle pain or weakness, known as myopathy. In rare but severe cases, this can develop into rhabdomyolysis, where muscle breakdown leads to serious complications. According to TheNNT.com, the NNH for muscle damage or discomfort is 10. This means that for every 10 people taking statins, one will experience muscle-related side effects. This is a significant figure and one that leads many patients to reconsider whether they should remain on the medication.
Diabetes Risk
There is also an increased risk of developing type2 diabetes among statin users. Studies suggest that statins can impair insulin sensitivity, leading to higher blood sugar levels, which, over time, may contribute to the onset of type 2 diabetes. The NNH for developing diabetes due to statins is 50. Therefore, for every 50 people treated with statins for 5 years, one additional person may develop diabetes.
Liver Damage
Statins are processed in the liver, and in rare cases, they can cause liver damage. Although the risk of significant liver injury is low, it is still a concern, especially when considering long-term use. Regular monitoring of liver function is typically recommended for those on statins.
Cognitive Decline and Memory Issues
Some patients report memory problems or cognitive decline (ie symptoms of Alzheimers or Dementia ) from taking statins, although the evidence is mixed. While there is as yet no specific NNH for these cognitive side effects, people should be aware that any unusual symptoms should prompt a discussion with their healthcare provider.
Overprescription and the Case for Lifestyle Changes
One of the concerns raised by critics, including our founder Graham Phillips, is the widespread overprescription of statins, particularly in primary prevention. As we’ve seen, the NNT for primary prevention is high, and the risk of side effects like muscle pain (NNH of 10) and diabetes (NNH of 50) can make the cost-benefit ratio less favourable for people with low to moderate cardiovascular risk.
At ProLongevity, we advocate for lifestyle-first approaches to managing cardiovascular risk, especially in people who fall into the primary prevention category. Sustainable changes in diet, exercise, and weight management have profound effects on heart health and can significantly reduce the need for medications like statins.
Lifestyle changes include:
- A heart-healthy diet, low in carbs and based on real foods.
- Regular physical activity, including aerobic exercise and resistance training, which helps improve cardiovascular health and cholesterol levels.
- Quitting smoking and reducing alcohol intake, both of which have been shown to improve heart health and reduce the risk of cardiovascular events.
- Managing stress and getting good quality sleep
These interventions are more effective than medications, and without the risks and side effects.
Nutritional Supplements:
Just as you can’t our-run a bad diet, neither can you out-supplement a bad diet either. But supplements CAN be helpful in addition to lifestyle changes
Making an Informed Decision
The decision to start or continue statin therapy should be based on an individual’s overall cardiovascular risk profile, health status, and personal preferences. For individuals at high risk of cardiovascular events (secondary prevention), statins provide a small, clear benefit, with a favourable NNT compared to the NNH for serious side effects. However, for those at lower risk (primary prevention), the balance between benefit and harm is more nuanced.
It’s essential to have an informed discussion with your healthcare provider, considering the NNT and NNH alongside other factors like lifestyle changes and alternative treatments.
Conclusion
Statins can be a life-saving intervention, especially for those at high risk of cardiovascular events, but they are not without their downsides. Understanding the Number Needed to Treat (NNT) and Number Needed to Harm (NNH) helps provide a clearer picture of the risk-benefit ratio for both primary and secondary prevention.
At ProLongevity, we focus on personalised care, helping people make informed choices based on their individual risk profiles and health goals. Whether that involves medication, lifestyle changes, or a combination of both, the key is to take a proactive approach to heart health that best suits your needs.
If you’re considering statins or experiencing side effects, we recommend discussing your options with a health professional. Together, you can explore the best strategy for managing your cardiovascular risk, ensuring that any treatment is as effective and safe as possible.
By incorporating tools like TheNNT.com, you can better understand the real-world impact of treatments like statins, helping you make a decision that is truly aligned with your long-term health and well-being.
For more information look at some of our other blogs and youtube interviews
https://www.prolongevity.co.uk/statin-the-bleedin-obvious/
https://www.prolongevity.co.uk/our-guide-to-a-healthy-heart/